Tool for friction stir welding

ABSTRACT

A tool for friction stir welding includes a tool part, a shank part and a cap part. The tool part and the shank part have a hexagonal frustum-shaped concave section and a hexagonal frustum-shaped convex section to enable movement of the tool part with respect to the shank part in a direction parallel to an axis of rotation while movement of the tool part with respect to the shank part in a direction around the axis of rotation is restricted, by the hexagonal frustum-shaped concave section and the hexagonal frustum-shaped convex section of the tool part and the shank part are fitted to each other. After the hexagonal frustum-shaped concave section and the hexagonal frustum-shaped convex section are fitted to each other, by the tool part and the shank part being covered by the cap part, the tool part is fixed to the shank part.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional Application of U.S. patent applicationSer. No. 14/912,691, filed Feb. 18, 2016, which is the U.S. NationalPhase Application of International Patent Application No.PCT/JP2014/071670, filed Aug. 19, 2014, which claims benefit of JapanesePatent Application No. 2013-170997, filed Aug. 21, 2013, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

An aspect of the present invention relates to a tool for friction stirwelding, and particularly, to a tool for friction stir welding includinga tool part and a shank part having a front end to which the tool partis fixed.

BACKGROUND ART

In recent years, development of a technology of welding and repair usinga friction stir effect is remarkable. Using friction stir welding, alarge number of successful examples of welding that could not beperformed in the welding of the related art, such as welding betweenhigh carbon steels, dissimilar welding of steel and Al alloy, weldingbetween Ti and alloys thereof that requires a high vacuum level forwelding, and so on, have been reported. Since friction stir welding is atechnology in which Al is used as a target of a material to be welded atthe beginning of development, a material that can be relatively easilyavailable, for example, tool steel or the like, can be used for the toolthat is used. For this reason, problems related to the tool are focusedon a shape of a probe or a shoulder that exerts an influence on a joint,such as a plastic flow, stirring efficiency, or the like.

Meanwhile, in recent years, developments in friction stir welding havebeen remarkable in a technology of welding or repairing a steelmaterial, a Ti-based alloy or a Ni alloy having a melting point about1000° C. higher than that of Al. When these materials are welded orrepaired, a tool having strength against high temperatures and goodabrasion resistance is needed. Until now, tools having high performanceat high temperatures such as ceramic-based tools obtained by sinteringcBN (cubic boron nitride) or Si₃N₄ (silicon nitride), metal-based toolssuch as Ni-based alloys, Co-based alloys, Mo-based alloys, W-basedalloys, Ir-based alloys, or the like, and so on, have been developed,and welding of metals having a high melting point come to be realize.

Since such a tool formed of an Ir-based alloy or the like is generallyexpensive, a technique of manufacturing only the tool that partiallycontributes to welding or repair and a holder configured to hold thetool using an inexpensive material and assembling the tool portion andthe holder is employed. For example, in Patent Document 1, a tool forfriction stir welding having a cutout as a locking section formed at arear section side of the tool that is detachably attached to a shankpart is disclosed. An accommodating section into which a rear sectionside of the tool having the locking section is inserted is formed in theshank part formed of tool steel or dies steel. As the rear section sideof the tool is inserted into the accommodating section of the shank partand a screw that is screwed thereinto is pressed against the lockingsection of the tool inserted into the accommodating section from a sidesurface of the shank part, the tool is fixed to the shank part.

PRIOR ART DOCUMENTS Patent Document

Patent Document 1: Japanese Published Unexamined Patent Application,First Publication No. 2005-199281

SUMMARY OF INVENTION Problems to be Resolved by the Invention

Incidentally, when the metal having a high melting point is welded, heatis transferred to not only the tool but also the holder that holds thetool, and further, high torsional stress is applied thereto. Thesebecome causes of burning and/or biting between the tool and the holder,and detachment of the tool may be difficult. In addition, when the tooland the holder are assembled by a method such as shrinkage fitting orthe like, the fitting may become loose due to heating, and a rotationalforce from the holder fixed to a power source may not be sufficientlytransmitted to the tool. In addition, the tool sometimes easily fallsout of the holder too easily.

In this technical field, it is desired to provide a tool for frictionstir welding capable of more reliably fixing a tool part to a shank partand easily detaching the tool part from the shank part.

Means of Solving the Problems

An aspect of the present invention is a tool for friction stir weldingcomprising: a tool part abutting a workpiece while being rotated; ashank part configured to fix the tool part to a front end of the shankpart and be rotated together with the tool part; and a cap partconfigured to cover the tool part and the shank part, wherein portionsin the tool part and the shank part at which the tool part and the shankpart contact each other have at least one from between a convex sectionand a concave section, in order to enable movement of the tool part withrespect to the shank part in a direction parallel to an axis of rotationof the shank part while movement of the tool part with respect to theshank part in a direction around the axis of rotation of the shank partis restricted, by the convex section and the concave section of the toolpart and the shank part being fitted to each other, and after the convexsection and the concave section of the tool part and the shank part arefitted to each other, the tool part is fixed to the front end of theshank part, by the tool part and the shank part being covered by the cappart.

According to the above-mentioned configuration, in the tool for frictionstir welding, when the tool part is fixed to the shank part by the cappart, since movement of the tool part with respect to the shank part inthe direction around the axis of rotation of the shank part isrestricted by the convex section and the concave section that are fittedto each other and movement of the tool part with respect to the shankpart in the direction parallel to the axis of rotation of the shank partis restricted by the cap part, it is possible to reliably prevent thetool part from being deviated with respect to the shank part in thedirection around the axis of rotation of the shank part upon rotation ofthe shank part, fixation of the tool part and the shank part from beingloosened, and the tool part from falling out of the shank part.

Meanwhile, when the cap part is detached, even when the convex sectionand the concave section are fitted to each other, since the tool partcan move with respect to the shank part in the direction parallel to theaxis of rotation of the shank part, the tool part can be easily detachedfrom the shank part.

In addition, another aspect of the present invention is a tool forfriction stir welding comprising: a tool part abutting a workpiece whilebeing rotated; a shank part configured to fix the tool part to a frontend of the shank part and be rotated together with the tool part; and ascrew having a groove formed at its outer periphery thereof for fixingthe tool part to the front end of the shank part, wherein portions inthe tool part and the shank part at which the tool part and the shankpart contact each other have at least one from between a convex sectionand a concave section, in order to enable movement of the tool part withrespect to the shank part in a direction parallel to an axis of rotationof the shank part while movement of the tool part with respect to theshank part in a direction around the axis of rotation of the shank partis restricted, by the convex section and the concave section of the toolpart and the shank part being fitted to each other, the shank part has ashank part hole section wherein the screw is capable of reaching thetool part fixed to the front end of the shank part passing through theshank part, the tool part has a tool part screw hole section having agroove, at an inner periphery, meshing with the groove of the outerperiphery of the screw passing through the shank part hole section, andafter the convex section and the concave section of the tool part andthe shank part are fitted to each other, the tool part is fixed to thefront end of the shank part, by the groove of the outer periphery of thescrew passed through the shank part hole section meshing with the grooveof the inner periphery of the tool part screw hole section.

According to the above-mentioned configuration, in the tool for frictionstir welding, after the convex section and the concave section of thetool part and the shank part are fitted to each other, as the screwpassing through the shank part hole section is screwed into the toolpart screw hole section, since movement of the tool part with respect tothe shank part in the direction around the axis of rotation of the shankpart is restricted by the convex section and the concave section thatare fitted to each other, the groove of the outer periphery of the screwis meshed with the groove of the inner periphery of the tool part screwhole section and the tool part is pulled and fixed to the shank part.

Since movement of the tool part with respect to the shank part in thedirection around the axis of rotation of the shank part is restricted bythe convex section and the concave section that are fitted to each otherand movement of the tool part with respect to the shank part in thedirection parallel to the axis of rotation of the shank part isrestricted by the screw, it is possible to reliably prevent the toolpart from being deviated with respect to the shank part in the directionaround the axis of rotation of the shank part upon rotation of the shankpart, fixation of the tool part and the shank part from being loosened,and the tool part from falling out of the shank part.

Meanwhile, in a state in which movement of the screw in the directionparallel to the axis of rotation of the shank part is restricted, as thescrew is rotated away from the tool part screw hole section, whilemovement of the tool part with respect to the shank part in thedirection around the axis of rotation of the shank part is restricted bythe convex section and the concave section that are fitted to eachother, since the tool part can move with respect to the shank part inthe direction parallel to the axis of rotation of the shank part, thegroove of the outer periphery of the screw is meshed with the groove ofthe inner periphery of the tool part screw hole section, and the toolpart is detached from the shank part by applying the force in thedirection away from the shank part. Accordingly, the tool part can beeasily detached from the shank part.

In this case, the tool may have a groove with an inner diameter largerthan an inner diameter of the tool part screw hole section in an innerperiphery of the shank part hole section, and the groove may be capableof screwing in a tool part detachment screw having a groove on its outerperiphery meshing with the groove of the inner periphery of the shankpart hole section.

According to the above-mentioned configuration, as the groove having alarger diameter than the tool part screw hole section is formed in theshank part hole section and the tool part detachment screw having adiameter set to be meshed with the groove is screwed thereinto, the toolpart is pushed out. Accordingly, the tool part can be easily detachedfrom the shank part.

In addition, the groove of the outer periphery of the screw and thegroove of the inner periphery of the tool part screw hole section may beformed such that the screw moves in an inward direction of the tool partscrew hole section when the screw is rotated in the same direction asthe rotational direction of the shank part.

According to the above-mentioned configuration, upon rotation of theshank part, since the force is applied in the direction in which thescrew moves in the inward direction of the tool part screw hole section,it is possible to more effectively prevent fixation of the tool part andthe shank part from being loosened and the tool part from falling out ofthe shank part as the screw is loosened.

In addition, the convex section may be a shape protruding in either apolygonal conical shape or a polygonal frustum shape, and the concavesection may be a shape recessed in either a polygonal conical shape or apolygonal frustum shape.

According to the above-mentioned configuration, the tool part can easilymove with respect to the shank part in the direction parallel to theaxis of rotation of the shank part while restricting movement of thetool part with respect to the shank part in the direction around theaxis of rotation of the shank part due to the simple shape.

In addition, the convex section may be a protruding shape as a key, andthe concave section may have a recessed shape as a key groove.

According to the above-mentioned configuration, the tool part can easilymove with respect to the shank part in the direction parallel to theaxis of rotation of the shank part while securely restricting movementof the tool part with respect to the shank part in the direction aroundthe axis of rotation of the shank part due to the simple shape.

In addition, the convex section may have a serrated shape including asurface parallel to the axis of rotation of the shank part andperpendicular to the direction around the axis of rotation, and theconcave section may have a serrated shape including a surface parallelto the axis of rotation of the shank part and perpendicular to adirection around the axis of rotation.

According to the above-mentioned configuration, as the surfacesperpendicular to the direction around the axis of rotation abut eachother, the tool part can move with respect to the shank part in thedirection parallel to the axis of rotation of the shank part whilesecurely restricting movement of the tool part with respect to the shankpart in the direction around the axis of rotation of the shank part.

In addition, the convex section may have a serrated shape including asurface parallel to the axis of rotation of the shank part andperpendicular to a direction around the axis of rotation, and theconcave section may have a serrated shape including a surface parallelto the axis of rotation of the shank part and perpendicular to thedirection around the axis of rotation, and the tool may be furtherprovided with a nut having a groove at its inner periphery meshing withthe groove of the outer periphery of the screw, the nut having an outerdiameter larger than an inner diameter of the shank part hole section,wherein the screw passes through the nut while the groove of the outerperiphery of the screw and the groove of the inner periphery of the nutare meshed with each other, the convex section and the concave sectionof the tool part and the shank part are fitted to each other, and afterthe groove of the outer periphery of the screw passing through the shankpart hole section is meshed with the groove of the inner periphery ofthe tool part screw hole section, in a state in which the shank part isdisposed between the tool part and the nut, the tool part may be fixedto the front end of the shank part by the nut being rotated in adirection in which the nut and the tool part approach each other, andthe tool part may be detached from the front end of the shank part bythe screw being rotated in a direction in which surfaces perpendicularto the direction around the axis of rotation of the serrated shapesfitted to each other separate from each other, after the nut is rotatedin a direction in which the nut and the tool part recede from eachother.

In the above-mentioned configuration, as the screw is screwed into thetool part through the shank part to fasten the nut, the tool part isreliably fixed to the front end of the shank part, and then the nut isloosened to rotate the screw, the serrated inclined surface of the toolpart and the serrated inclined surface of the shank part slide inopposite directions, and the tool part is detached from the shank partby applying the force in the direction away from the shank part.Accordingly, the tool part can be detached from the shank part.

In addition, in the case that the convex section has a serrated shapeincluding a surface parallel to the axis of rotation of the shank partand perpendicular to a direction around the axis of rotation, and theconcave section has a serrated shape including a surface parallel to theaxis of rotation of the shank part and perpendicular to the directionaround the axis of rotation, after the screw is removed from the toolpart screw hole section and the shank part hole section, a tool partdetachment screw having a groove at its outer periphery meshing with thegroove of the inner periphery of the tool part screw hole section passesthrough the shank part hole section, and the groove of the outerperiphery of the tool part detachment screw is meshed with the groove ofthe inner periphery of the tool part screw hole section, and the toolpart may be detached from the front end of the shank part by the toolpart detachment screw being rotated in a direction in which surfacesperpendicular to the direction around the axis of rotation of theserrated shapes fitted to each other separate from each other.

In the above-mentioned configuration, as the screw is screwed into theshank part and the tool part, the tool part can be reliably fixed to thefront end of the shank part. Then, as the screw is detached from theshank part, the tool part detachment screw is screwed into the tool partscrew hole section through the shank part hole section and the screw isfurther rotated, the serrated inclined surface of the tool part and theserrated inclined surface of the shank part slide together, and the toolpart is detached from the shank part by applying the force in thedirection separating from the shank part. Accordingly, the tool part canbe easily detached from the shank part.

In addition, another aspect of the present invention is a tool forfriction stir welding comprising: a tool part abutting a workpiece whilebeing rotated; a shank part configured to fix the tool part to a frontend of the shank part and be rotated together with the tool part; and asliding restriction member fixed to a portion at which the tool part andthe shank part contact each other, wherein a portion of the tool partand the shank part in which the tool part and the shank part contacteach other have at least one from between a dovetail-shaped sectionprotruding in a trapezoidal shape and a dovetail groove section recessedin a trapezoidal shape, the dovetail-shaped section protruding in atrapezoidal shape and the dovetail groove section recessed in atrapezoidal shape enabling slide movement of the tool part with respectto the shank part in a direction perpendicular to an axis of rotation ofthe shank part while movement of the tool part with respect to the shankpart in a direction parallel to the axis of rotation of the shank partis restricted by the dovetail-shaped section and the dovetail groovesection of the tool part and the shank part being fitted to each other,and after the dovetail-shaped section and the dovetail groove section ofthe tool part and the shank part are fitted to each other, the tool partis fixed to the front end of the shank part so as to restrict slidemovement of the tool part with respect to the shank part in thedirection perpendicular to the axis of rotation of the shank part, bythe sliding restriction member being fixed to the portion at which thetool part and the shank part contact each other.

According to the above-mentioned configuration, when the slidingrestriction member is fixed to the portion at which the tool part andthe shank part come in contact with each other, since movement of thetool part with respect to the shank part in the direction parallel tothe axis of rotation of the shank part by the dovetail-shaped sectionand the dovetail groove section that are fitted to each other andsliding movement of the tool part with respect to the shank part in thedirection perpendicular to the axis of rotation of the shank part isrestricted by the sliding restriction member, upon rotation of the shankpart, it is possible to reliably prevent fixation of the tool part andthe shank part from being loosened and the tool part from falling out ofthe shank part.

Meanwhile, when the sliding restriction member is detached, even whenthe dovetail-shaped section and the dovetail groove section are fittedto each other, since the tool part can move with respect to the shankpart in the direction perpendicular to the axis of rotation of the shankpart, the tool part can be easily detached from the shank part.

In this case, the tool may further comprise a detachment memberreceiving section capable of having attached thereto a detachment memberfor applying a force such that the tool part slides with respect to theshank part in the direction perpendicular to the axis of rotation of theshank part when the dovetail-shaped section and the dovetail groovesection of the tool part and the shank part are fitted to each other andthe sliding restriction member is not fixed to the portion at which thetool part and the shank part contact each other.

According to the above-mentioned configuration, as the detachment memberis attached to the detachment member receiving section and a force isapplied by the detachment member such that the tool part slides withrespect to the shank part in the direction perpendicular to the axis ofrotation of the shank part, even when the tool part is hard to remove,the tool part can be easily detached from the shank part.

Advantageous Effects of the Invention

According to the tool for friction stir welding of the above-mentionedaspects and other aspects of the present invention, loosening offixation between the tool part and the shank part and removal of thetool part from the shank part can be reliably prevented, and the toolpart can be easily detached from the shank part.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing a shank part, a tool part and a cap partaccording to a first embodiment.

FIG. 2 is a plan view of the tool part of FIG. 1 when seen from adirection of an arrow A.

FIG. 3 is a side view showing a shank part, a tool part and a cap partaccording to a second embodiment.

FIG. 4 is a plan view of the tool part of FIG. 3 when seen from adirection of an arrow B.

FIG. 5 is a side view showing a shank part, a tool part and a cap partaccording to a third embodiment.

FIG. 6 is a plan view of the tool part of FIG. 5 when seen from adirection of an arrow C.

FIG. 7 is a side view showing a shank part, a tool part and a cap partaccording to a fourth embodiment.

FIG. 8 is a plan view of the tool part of FIG. 7 when seen from adirection of an arrow D.

FIG. 9 is a side view showing a screw, a shank part and a tool partaccording to a fifth embodiment.

FIG. 10 is a plan view of the tool part of FIG. 9 when seen from adirection of an arrow E.

FIG. 11 is a longitudinal cross-sectional view showing a state in whichthe tool part is fixed to the shank part using the screw of FIG. 9.

FIG. 12 is a longitudinal cross-sectional view showing a state in whichthe screw is detached from the state of FIG. 11 and a tool partdetachment screw is screwed into the shank part.

FIG. 13 is a longitudinal cross-sectional view showing a state in whichthe tool part is detached from the shank part as the tool partdetachment screw is screwed further thereinto from the state of FIG. 12.

FIG. 14 is a side view showing a screw, a shank part and a tool partaccording to a sixth embodiment.

FIG. 15 is a plan view of a tool for friction stir welding of FIG. 14when seen from a direction of an arrow E

FIG. 16 is a side view showing a screw, a shank part and a tool partaccording to a seventh embodiment.

FIG. 17 is a plan view of a tool for friction stir welding of FIG. 16when seen from a direction of an arrow G

FIG. 18 is a side view showing a screw, a shank part and a tool partaccording to an eighth embodiment.

FIG. 19 is a plan view of a tool for friction stir welding of FIG. 18when seen from a direction of an arrow H.

FIG. 20 is a side view showing a screw, a nut, a shank part and a toolpart according to a ninth embodiment.

FIG. 21 is a plan view of a tool for friction stir welding of FIG. 20when seen from a direction of an arrow I.

FIG. 22 is a partial cross-sectional view showing a state in which thetool part is fixed to the shank part using the screw and the nut of FIG.20.

FIG. 23 is a partial cross-sectional view showing a state in which thenut is rotated away from the tool part from the state of FIG. 22.

FIG. 24 is a partial cross-sectional view showing a state in which thescrew is rotated from the state of FIG. 23 to detach the tool part fromthe shank part in a direction in which a serrated vertical surface ofthe tool part and a serrated vertical surface of the shank part areseparated from each other.

FIG. 25 is a side view showing a screw, a shank part and a tool partaccording to a tenth embodiment.

FIG. 26 is a plan view of a tool for friction stir welding of FIG. 25when seen from a direction of an arrow J.

FIG. 27 is a partial cross-sectional view showing a state in which thetool part is fixed to the shank part using the screw of FIG. 25.

FIG. 28 is a partial cross-sectional view showing a state in which thescrew is removed from the state of FIG. 27 and a tool part detachmentscrew is screwed into the tool part through the shank part.

FIG. 29 is a partial cross-sectional view showing a state in which thetool part detachment screw is rotated from the state of FIG. 28 todetach the tool part from the shank part in a direction in which aserrated vertical surface of the tool part and a serrated verticalsurface of the shank part are separated from each other.

FIG. 30 is a perspective view showing a shank part, a tool part and alid according to an eleventh embodiment.

FIG. 31 is a plan view of the assembled shank part, tool part and lid ofFIG. 30 when seen from a direction of an arrow K.

FIG. 32 is a cross-sectional view taken along line L-L of FIG. 31.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.

As shown in FIG. 1, a tool for friction stir welding 10 a according to afirst embodiment of the present invention includes a shank part 100 a, atool part 200 a and a cap part 300.

The shank part 100 a has a columnar shape as a whole. The shank part 100a fixes the tool part 200 a to a front end thereof at a lower end inFIG. 1, and is rotated about an axis of rotation 11 by a power source(not shown) together with the tool part 200 a. The shank part 100 a canbe manufactured using a relatively inexpensive material such as toolsteel or the like. A screw hole section configured to fix the cap part300 using a screw may be formed at a circumferential edge or an outerperiphery of the front end of the shank part 100 a. Alternatively, agroove configured to fix the cap part 300 may be formed in the outerperiphery of the front end of the shank part 100 a.

The tool part 200 a is fixed to the front end of the shank part 100 a,and abuts a workpiece while rotating. The tool part 200 a has a columnarshoulder 201 protruding from a conical frustum or columnar base section205 at the front end portion abutting the workpiece. While the basesection 205 will be described using a conical frustum base section inFIG. 1 and the other embodiments described below, the base section maybe variously modified to a shape such as a columnar shape or the like. Aconical frustum probe 202 having a bottom surface with a smallerdiameter than the shoulder 201 protrudes from a center of the front endof the shoulder 201. When the workpiece having a high melting point andformed of a steel material, a Ti-based alloy, a Ni alloy, or the like,is welded, the tool part 200 a is manufactured using an Ir-based alloyor the like. In the embodiment, since the tool part 200 a has a minimumsize that enables the friction stir welding, even when the tool part ismanufactured using a relatively expensive material such as an Ir alloyor the like, manufacturing cost can be reduced.

The cap part 300 has a cylindrical shape as a whole. The cap part 300may be manufactured using a relatively inexpensive material such as toolsteel or the like. The cap part 300 has a cap part inner surface 301.The cap part inner surface 301 has a shape corresponding to a shape ofthe front end of the shank part 100 a. The cap part inner surface 301has a reduced diameter section 302 having an inner diameter reduced atthe end portion. The reduced diameter section 302 has a shapecorresponding to a shape of the conical frustum or columnar base section205 of the tool part 200 a, and an inner diameter smaller than the outerdiameter of the conical frustum or columnar base section 205 and equalto or larger than the outer diameter of the shoulder 201. A hole sectioncorresponding to a screw hole section of the shank part 100 a may beformed in the cap part 300 to be fixed to the front end of the shankpart 100 a. Alternatively, in order to fix the cap part to the front endof the shank part 100 a, a groove corresponding to the groove formed inthe outer periphery of the front end of the shank part 100 a may beformed in the cap part inner surface 301.

A hexagonal frustum-shaped concave section 121 recessed in a hexagonalfrustum shape is formed in the front end of the shank part 100 a. Theside surface of the hexagonal frustum-shaped concave section 121 isinclined toward the axis of rotation 11 of the shank part 100 a whilereaching the inside of the shank part 100 a from the front end of theshank part 100 a. Further, the hexagonal frustum-shaped concave section121 is not limited to the hexagonal frustum shape but may have shapes ofa quadrangular pyramid, an octagonal pyramid or other polygonalpyramids, and a quadrangular frustum, an octagonal frustum or otherpolygonal frustums.

As shown in FIGS. 1 and 2, a hexagonal frustum-shaped convex section 211corresponding to a shape of the hexagonal frustum-shaped concave section121 of the shank part 100 a is formed at a portion of the base section205 of the tool part 200 a that comes in contact with the shank part 100a. The side surface of the hexagonal frustum-shaped convex section 211is inclined toward the axis of rotation 11 of the shank part 100 a thatserves as an axis of rotation of the tool part 200 a as separated fromthe base section 205 of the tool part 200 a. Further, the hexagonalfrustum-shaped convex section 211 is not limited to the hexagonalfrustum shape but may have shapes of a quadrangular pyramid, anoctagonal pyramid or other polygonal pyramids, and a quadrangularfrustum, an octagonal frustum or other polygonal frustums.

Hereinafter, an action of the tool for friction stir welding 10 a of theembodiment will be described. When the friction stir welding isperformed using the tool for friction stir welding 10 a, the hexagonalfrustum-shaped concave section 121 of the shank part 100 a and thehexagonal frustum-shaped convex section 211 of the tool part 200 a arefitted to each other. Since both of the hexagonal frustum-shaped concavesection 121 and the hexagonal frustum-shaped convex section 211 have ahexagonal frustum shape, movement of the tool part 200 a with respect tothe shank part 100 a in a direction parallel to the axis of rotation 11of the shank part 100 a becomes possible while movement of the tool part200 a with respect to the shank part 100 a in a direction around theaxis of rotation 11 of the shank part 100 a is restricted.

In a state in which the hexagonal frustum-shaped concave section 121 andthe hexagonal frustum-shaped convex section 211 are fitted to eachother, as the front end of the shank part 100 a and the base section 205of the tool part 200 a are covered by the cap part 300 attached to theshank part 100 a, the tool part 200 a is fixed to the front end of theshank part 100 a. Here, the shoulder 201 and the probe 202 of the toolpart 200 a are exposed from the cap part 300. In this way, the frictionstir welding can be performed in a state in which the tool part 200 a isfixed to the front end of the shank part 100 a. When the tool part 200 ais detached from the shank part 100 a, as the cap part 300 is detachedfrom the shank part 100 a and the tool part 200 a, the tool part 200 acan be easily detached from the shank part 100 a. Further, applicationof a release agent such as BN or the like to the hexagonalfrustum-shaped concave section 121, the hexagonal frustum-shaped convexsection 211 and the cap part inner surface 301 that come in contact witheach other is effective to prevent burning.

According to the embodiment, the tool for friction stir welding 10 aincludes the tool part 200 a abutting the workpiece while rotating, theshank part 100 a having the front end to which the tool part 200 a isfixed and rotated together with the tool part 200 a, and the cap part300 configured to cover the tool part 200 a and the shank part 100 a.The hexagonal frustum-shaped concave section 121 and the hexagonalfrustum-shaped convex section 211 are provided at portions of the toolpart 200 a and the shank part 100 a at which the tool part 200 a and theshank part 100 a come in contact with each other, such that the toolpart 200 a can move with respect to the shank part 100 a in thedirection parallel to the axis of rotation of the shank part 100 a whilemovement of the tool part 200 a with respect to the shank part 100 a inthe direction around the axis of rotation 11 of the shank part 100 a isrestricted as the tool part and the shank part are fitted to each other.After the hexagonal frustum-shaped concave section 121 and the hexagonalfrustum-shaped convex section 211 of the tool part 200 a and the shankpart 100 a are fitted to each other, as the tool part 200 a and theshank part 100 a are covered by the cap part 300, the tool part 200 a isfixed to the front end of the shank part 100 a.

For this reason, when the tool part 200 a is fixed to the shank part 100a by the cap part 300, since movement of the tool part 200 a withrespect to the shank part 100 a in the direction around the axis ofrotation 11 of the shank part 100 a is restricted by the hexagonalfrustum-shaped concave section 121 and the hexagonal frustum-shapedconvex section 211 that are fitted to each other and movement of thetool part 200 a with respect to the shank part 100 a in the directionparallel to the axis of rotation 11 of the shank part 100 a isrestricted by the cap part 300, it is possible to reliably prevent thetool part 200 a from being deviated with respect to the shank part 100 ain the direction around the axis of rotation 11 of the shank part 100 aupon rotation of the shank part 100 a, fixation of the tool part 200 aand the shank part 100 a from being loosened, or the tool part 200 afrom falling out of the shank part 100 a.

Meanwhile, when the cap part 300 is detached, even though the hexagonalfrustum-shaped concave section 121 and the hexagonal frustum-shapedconvex section 211 are fitted to each other, since the tool part 200 acan move with respect to the shank part 100 a in the direction parallelto the axis of rotation 11 of the shank part 100 a, the tool part 200 acan be easily detached from the shank part 100 a.

In addition, in the embodiment, the hexagonal frustum-shaped concavesection 121 is recessed in a hexagonal frustum shape, and the hexagonalfrustum-shaped convex section 211 protrudes in a hexagonal frustumshape. For this reason, the tool part 200 a can be easily moved withrespect to the shank part 100 a in the direction parallel to the axis ofrotation 11 of the shank part 100 a while restricting movement of thetool part 200 a with respect to the shank part 100 a in the directionaround the axis of rotation 11 of the shank part 100 a due to the simpleshape. In addition, in the embodiment, since the hexagonalfrustum-shaped convex section 211 protrudes from the tool part 200 aabutting the workpiece and a length of the tool part 200 a along theaxis of rotation 11 is increased, strength of the tool part 200 a can beimproved.

Hereinafter, a second embodiment of the present invention will bedescribed. As shown in FIGS. 3 and 4, a tool for friction stir welding10 b of the embodiment is distinguished from the first embodiment inthat the same hexagonal frustum-shaped convex section 111 as thehexagonal frustum-shaped convex section 211 of the tool part 200 a ofthe first embodiment is provided at a shank part 100 b and the samehexagonal frustum-shaped concave section 221 as the hexagonalfrustum-shaped concave section 121 of the shank part 100 a of the firstembodiment is provided at a tool part 200 b. The other configurationsand actions of the tool for friction stir welding 10 b are the same asthe first embodiment.

In the embodiment, since the hexagonal frustum-shaped concave section221 is recessed in the tool part 200 b abutting the workpiece, even whenthe tool part is manufactured using a relatively expensive material suchas an Ir alloy or the like, manufacturing cost can be reduced whilereducing an amount of the material used.

Hereinafter, a third embodiment of the present invention will bedescribed. As shown in FIG. 5, in a tool for friction stir welding 10 cof the embodiment, a conical frustum concave section 122 recessed in aconical frustum shape is formed at a center of a front end of a shankpart 100 c. A side surface of the conical frustum concave section 122 isinclined toward the axis of rotation 11 of the shank part 100 c whilereaching the inside of the shank part 100 c from the front end of theshank part 100 c. In addition, keys 131 protruding in a directionparallel to the axis of rotation 11 at positions of 0° and 180° aroundthe axis of rotation 11 are formed at a circumferential edge of thefront end of the shank part 100 c. These keys 131 may be disposed atpositions of 0°, 90°, 180° and 270° around the axis of rotation 11 in across shape. In addition, an arbitrary number of keys 131 may bedisposed.

As shown in FIGS. 5 and 6, a conical frustum convex section 212corresponding to a shape of the conical frustum concave section 122 ofthe shank part 100 c is formed at a portion of a base section 205 of atool part 200 c that comes in contact with the shank part 100 c. Theside surface of the conical frustum convex section 212 is inclinedtoward the axis of rotation 11 of the shank part 100 c serving as theaxis of rotation of the tool part 200 c while being separated from thebase section 205 of the tool part 200 c. Key grooves 232 recessed in adirection parallel to the axis of rotation 11 at positions of 0° and180° around the axis of rotation 11 are formed in a circumferential edgeof the base section 205 of the tool part 200 c to correspond to shapesof the keys 131 of the shank part 100 c. These key grooves 232 may bedisposed at positions of 0°, 90°, 180° and 270° around the axis ofrotation 11 in a cross shape. In addition, an arbitrary number of keygrooves 232 may be disposed.

Hereinafter, an action of the tool for friction stir welding 10 c of theembodiment will be described. When the friction stir welding isperformed using the tool for friction stir welding 10 c, the conicalfrustum concave section 122 of the shank part 100 c and the conicalfrustum convex section 212 of the tool part 200 c, and the key 131 ofthe shank part 100 c and the key groove 232 of the tool part 200 c arefitted to each other, respectively. Since both of the conical frustumconcave section 122 and the conical frustum convex section 212 have atruncated cone shape, the tool part 200 c can move with respect to theshank part 100 c in the direction parallel to the axis of rotation 11 ofthe shank part 100 c. Meanwhile, since the key 131 and the key groove232 are fitted to each other, movement of the tool part 200 c withrespect to the shank part 100 c in the direction around the axis ofrotation 11 of the shank part 100 c is restricted. Further, a releaseagent such as BN or the like is applied to the conical frustum concavesection 122, the conical frustum convex section 212, the key 131 and thekey groove 232 that come in contact with each other to effectivelyprevent burning.

In a state in which the conical frustum concave section 122 and theconical frustum convex section 212 are fitted to each other and the key131 and the key groove 232 are fitted to each other, as the front end ofthe shank part 100 c and the base section 205 of the tool part 200 c arecovered by the cap part 300, the tool part 200 c is fixed to the frontend of the shank part 100 c. Here, the shoulder 201 and the probe 202 ofthe tool part 200 c are exposed from the cap part 300. In this way, thefriction stir welding can be performed in a state in which the tool part200 c is fixed to the front end of the shank part 100 c. When the toolpart 200 c is detached from the shank part 100 c, as the cap part 300 isdetached from the shank part 100 c and the tool part 200 c, the toolpart 200 c can be easily detached from the shank part 100 c.

According to the embodiment, since the protruding key 131 and therecessed key groove 232 are provided, the tool part 200 c can move withrespect to the shank part 100 c in the direction parallel to the axis ofrotation 11 of the shank part 100 c while movement of the tool part 200c with respect to the shank part 100 c in the direction around the axisof rotation 11 of the shank part 100 c is reliably restricted due to thesimple shape. In addition, in the embodiment, since the conical frustumconvex section 212 protrudes from the tool part 200 c abutting theworkpiece and a length of the tool part 200 c along the axis of rotation11 is increased, strength of the tool part 200 c can be improved.

Hereinafter, a fourth embodiment of the present invention will bedescribed. As shown in FIGS. 7 and 8, a tool for friction stir welding10 d of the embodiment is distinguished from the third embodiment inthat the same conical frustum convex section 112 and the same key groove132 as the conical frustum convex section 212 and the key groove 232 ofthe tool part 200 c of the third embodiment are formed at a shank part100 d and the same conical frustum concave section 222 and the same key231 as the conical frustum concave section 122 and the key 131 of theshank part 100 c of the third embodiment are formed at a tool part 200d. The other configurations and actions of the tool for friction stirwelding 10 d are the same as the third embodiment.

In the embodiment, since the conical frustum concave section 222 isrecessed in the tool part 200 d abutting the workpiece, even when thetool part is manufactured using a relatively expensive material such asan Ir alloy or the like, manufacturing cost can be reduced by reducingan amount of the material used.

Hereinafter, a fifth embodiment of the present invention will bedescribed. As shown in FIG. 9, a tool for friction stir welding 10 eaccording to the fifth embodiment of the present invention includes ashank part 100 e, a tool part 200 e and a screw 400 e.

As shown in FIG. 9, the shank part 100 e of the embodiment isdistinguished from the first embodiment in that a hole section 141 isprovided such that a screw front end portion 402 of the screw 400 epasses through the shank part 100 e to reach the tool part 200 e fixedto the front end of the shank part 100 e. Further, while a groove is notnecessary to be formed in the inner periphery of the hole section 141, agroove meshed with a groove 404 of the outer periphery of the screw 400e may be formed in the inner periphery of the hole section 141. Further,as shown in FIG. 9, a groove 144 having a larger inner diameter than ascrew hole section 241 of the tool part 200 e may be formed at the innerperiphery of the hole section 141 such that a tool part detachment screwhaving an outer diameter set to be meshed with the groove 144 is screwedthereinto. In addition, a collar 213 having an inner diameter slightlylarger than the outer diameter of the tool part 200 e may be formed inthe shank part 100 e. A central axis of the tool part 200 e is easilymatched with the axis of rotation 11 of the shank part 100 e by thecollar 213. In addition, a load of the screw 400 e configured to connectthe shank part 100 e and the tool part 200 e is reduced by the collar213, and movement of the tool part 200 e from the shank part 100 e uponthe friction stir welding can be prevented.

As shown in FIGS. 9 and 10, the tool part 200 e of the embodiment isdistinguished from the first embodiment in that the screw hole section241 has a groove 244 formed in an inner periphery thereof and meshedwith the groove 404 of the outer periphery of the screw front endportion 402 of the screw 400 e that passes through the hole section 141.

As shown in FIG. 9, the screw 400 e has the screw front end portion 402having the groove 404 formed at the outer periphery and configured tofix the tool part 200 e to the front end of the shank part 100 e. Ascrew head section 401 having a larger diameter than the screw front endportion 402 and the hole section 141 is formed at an opposite side ofthe screw front end portion 402 of the screw 400 e. A length of thescrew 400 e excluding the screw head section 401 corresponds to a lengthobtained by adding a length of the hole section 141 of the shank part100 e and a length of the screw hole section 241 of the tool part 200 e.Further, while the groove 404 of the screw front end portion 402 may beformed within a range to be meshed with the groove 244 of the screw holesection 241 of the tool part 200 e, as shown in FIG. 9, the groove 404may be formed over the entire screw 400 e except for the screw headsection 401.

Further, the groove 404 of the outer periphery of the screw 400 e andthe groove 244 of the inner periphery of the screw hole section 241 ofthe tool part 200 e are formed in a direction in which the screw 400 emoves in an inward direction of the screw hole section 241 of the toolpart 200 e when the screw 400 e is rotated in the same direction as therotational direction of the shank part 100 e. For example, when thescrew grooves 404 and 244 formed in the screw 400 e and the tool part200 e are formed in a conventional direction in which the screw 400 emoves in the inward direction of the screw hole section 241 of the toolpart 200 e when the screw 400 e is rotated clockwise when seen from thescrew head section 401, the rotational direction of the shank part 100 eupon the friction stir welding becomes clockwise when seen from thescrew head section 401.

Hereinafter, an action of the tool for friction stir welding 10 e of theembodiment will be described. When the friction stir welding isperformed using the tool for friction stir welding 10 e, like the firstembodiment, the hexagonal frustum-shaped concave section 121 of theshank part 100 e and the hexagonal frustum-shaped convex section 211 ofthe tool part 200 e are fitted to each other. Since both of thehexagonal frustum-shaped concave section 121 and the hexagonalfrustum-shaped convex section 211 have the hexagonal frustum shape, thetool part 200 e can move with respect to the shank part 100 e in thedirection parallel to the axis of rotation 11 of the shank part 100 ewhile movement of the tool part 200 e with respect to the shank part 100e in the direction around the axis of rotation 11 of the shank part 100e is restricted.

In a state in which the hexagonal frustum-shaped concave section 121 andthe hexagonal frustum-shaped convex section 211 are fitted to eachother, as shown in FIG. 11, as the screw 400 e is inserted into the holesection 141 of the shank part 100 e while being rotated in a directionmoving in the inward direction of the screw hole section 241 of the toolpart 200 e and the groove 404 of the outer periphery of the screw 400 ethat passes through the hole section 141 of the shank part 100 e ismeshed with the groove 244 of the inner periphery of the screw holesection 241 of the tool part 200 e, the tool part 200 e is fixed to thefront end of the shank part 100 e. In this way, the friction stirwelding can be performed in a state in which the tool part 200 e isfixed to the front end of the shank part 100 e. Further, a release agentsuch as BN or the like is applied to the hexagonal frustum-shapedconcave section 121 and the hexagonal frustum-shaped convex section 211that come in contact with each other, the screw 400 e and the holesection 141, and the screw hole section 241 to effectively preventburning. When the tool part 200 e is detached from the shank part 100 e,in a state in which movement of the screw 400 e in the directionparallel to the axis of rotation 11 of the shank part 100 e isrestricted, as the screw 400 e is rotated away from the screw holesection 241 of the tool part 200 e, the tool part 200 e can be easilydetached from the shank part 100 e.

In addition, as shown in FIG. 9, when the groove 144 having a largerinner diameter than the screw hole section 241 of the tool part 200 e isformed in the hole section 141 of the shank part 100 e, first, the screw400 e is detached from the tool part 200 e and the shank part 100 e.

Next, as shown in FIG. 12, a tool part detachment screw 450 e having agroove 454 formed at an outer periphery thereof and meshed with thegroove 144 formed in the inner periphery of the hole section 141 of theshank part 100 e is screwed into the hole section 141. In an example ofFIG. 12, when seen from a screw head section 451 of the tool partdetachment screw 450 e, as the tool part detachment screw 450 e isrotated clockwise, a screw front end portion 452 of the tool partdetachment screw 450 e abuts the tool part 200 e. As shown in FIG. 13,as the tool part detachment screw 450 e is further rotated clockwisewhen seen from the screw head section 451, the tool part 200 e is pushedout by the screw front end portion 452 of the tool part detachment screw450 e, and the tool part 200 e is detached from the shank part 100 e.

According to the embodiment, after the hexagonal frustum-shaped convexsection 211 and the hexagonal frustum-shaped concave section 121 of thetool part 200 e and the shank part 100 e are fitted to each other, asthe screw 400 e passing through the hole section 141 of the shank part100 e is screwed into the screw hole section 241 of the tool part 200 e,since movement of the tool part 200 e with respect to the shank part 100e in the direction around the axis of rotation 11 of the shank part 100e is restricted by the hexagonal frustum-shaped convex section 211 andthe hexagonal frustum-shaped concave section 121 that are fitted to eachother, the groove 404 of the outer periphery of the screw 400 e ismeshed with the groove 244 of the inner periphery of the screw holesection 241 of the tool part 200 e, and the tool part 200 e is pulledand fixed to the shank part 100 e.

Since movement of the tool part 200 e with respect to the shank part 100e in the direction around the axis of rotation 11 of the shank part 100e is restricted by the hexagonal frustum-shaped convex section 211 andthe hexagonal frustum-shaped concave section 121 that are fitted to eachother and movement of the tool part 200 e with respect to the shank part100 e in the direction parallel to the axis of rotation 11 of the shankpart 100 e is restricted by the screw 400 e, it is possible to reliablyprevent the tool part 200 e from being deviated with respect to theshank part 100 e in the direction around the axis of rotation 11 of theshank part 100 e upon rotation the shank part 100 e, fixation of thetool part 200 e and the shank part 100 e from being loosened, and thetool part 200 e from falling out of the shank part 100 e.

Meanwhile, in a state in which movement of the screw 400 e in thedirection parallel to the axis of rotation 11 of the shank part 100 e isrestricted by rotation of the screw 400 e away from the screw holesection 241 of the tool part 200 e, since the tool part 200 e can movewith respect to the shank part 100 e in the direction parallel to theaxis of rotation 11 of the shank part 100 e, while movement of the toolpart 200 e with respect to the shank part 100 e in the direction aroundthe axis of rotation 11 of the shank part 100 e is restricted by thehexagonal frustum-shaped convex section 211 and the hexagonalfrustum-shaped concave section 121 that are fitted to each other, thegroove 404 of the outer periphery of the screw 400 e is meshed with thegroove 244 of the inner periphery of the screw hole section 241 of thetool part 200 e, and the tool part 200 e is detached from the shank part100 e by applying a force in a direction away from the shank part 100 e.Accordingly, the tool part 200 e can be easily detached from the shankpart 100 e.

In addition, as the groove 144 having a larger diameter than the screwhole section 241 of the tool part 200 e is formed in the hole section141 of the shank part 100 e and the tool part detachment screw 450 ehaving a diameter set to be meshed with the groove 144 is screwedthereinto, the tool part 200 e is detached from the shank part 100 e byapplying a force in a direction away from the shank part 100 e.Accordingly, the tool part 200 e can be easily detached from the shankpart 100 e.

In addition, in the embodiment, the groove 404 of the outer periphery ofthe screw 400 e and the groove 244 of the inner periphery of the screwhole section 241 of the tool part 200 e are configured such that thescrew 400 e is moved in the inward direction of the screw hole section241 of the tool part 200 e when the screw 400 e is rotated in the samedirection as the rotational direction of the shank part 100 e.Accordingly, upon rotation of the shank part 100 e, since a force isapplied in the direction in which the screw 400 e is moved in the inwarddirection of the screw hole section 241 of the tool part 200 e, it ispossible to effectively prevent fixation of the tool part 200 e and theshank part 100 e from loosening and the tool part 200 e from falling outof the shank part 100 e due to loosening of the screw 400 e.

In addition, in the embodiment, the hexagonal frustum-shaped concavesection 121 is recessed in a hexagonal frustum shape, and the hexagonalfrustum-shaped convex section 211 protrudes in a hexagonal frustumshape. For this reason, the tool part 200 e can be easily moved withrespect to the shank part 100 e in the direction parallel to the axis ofrotation 11 of the shank part 100 e while movement of the tool part 200e with respect to the shank part 100 e in the direction around the axisof rotation 11 of the shank part 100 e is restricted due to the simpleshape.

In addition, in the embodiment, since the hexagonal frustum-shapedconvex section 211 protrudes from the tool part 200 e abutting theworkpiece and a length of the tool part 200 e along the axis of rotation11 is increased, strength of the tool part 200 e can be improved.

Hereinafter, a sixth embodiment of the present invention will bedescribed. As shown in FIGS. 14 and 15, a tool for friction stir welding10 f of the embodiment is distinguished from the fifth embodiment inthat the same hexagonal frustum-shaped convex section 111 as thehexagonal frustum-shaped convex section 211 of the tool part 200 e ofthe fifth embodiment is provided at a shank part 100 f and the samehexagonal frustum-shaped concave section 221 as the hexagonalfrustum-shaped concave section 121 of the shank part 100 e of the fifthembodiment is provided at a tool part 200 f.

In addition, as shown in FIG. 14, the embodiment is distinguished fromthe fifth embodiment in that an increased hole diameter section 142having a larger inner diameter than the hole section 141 is formed atthe hole section 141 of the shank part 100 f close to the screw headsection 401. For this reason, a length of a screw 400 f excluding thescrew head section 401 corresponds to a length obtained by adding alength of the hole section 141 of the shank part 100 f smaller than thatof the fifth embodiment and a length of the screw hole section 241 ofthe tool part 200 f, and is smaller than that of the screw 400 e of thefifth embodiment. The other configurations and actions of the tool forfriction stir welding 10 f are the same as the fifth embodiment.

In the embodiment, since the hexagonal frustum-shaped concave section221 is recessed in the tool part 200 f abutting the workpiece, even whenthe tool part is manufactured using a relatively expensive material suchas an Ir alloy or the like, manufacturing cost can be reduced byreducing a use amount of the material. In addition, since the screw headsection 401 of the screw 400 f is accommodated in the increased holediameter section 142, when exposure of the screw head section 401 fromthe shank part 100 f is not preferable due to a situation in a facilitythat performs the friction stir welding, it is possible to preventexposure of the screw head section 401 from the shank part 100 f.

Hereinafter, a seventh embodiment of the present invention will bedescribed. As shown in FIGS. 16 and 17, a tool for friction stir welding10 g of the embodiment is distinguished from the sixth embodiment inthat, like the third embodiment, the conical frustum concave section 122and the key 131 are provided at a shank part 100 g and the conicalfrustum convex section 212 and the key groove 232 are provided at a toolpart 200 g. A length of a screw 400 g excluding the screw head section401 corresponds to a length obtained by adding a length of the holesection 141 of the shank part 100 g smaller than that of the fifthembodiment and a length of the screw hole section 241 of the tool part200 g, and is smaller than that of the screw 400 e of the fifthembodiment. The other configurations and actions of the tool forfriction stir welding 10 g are the same as the third embodiment and thesixth embodiment.

In the embodiment, since the protruding key 131 and the recessed keygroove 232 are provided, the tool part 200 g can move with respect tothe shank part 100 g in the direction parallel to the axis of rotation11 of the shank part 100 g while movement of the tool part 200 g withrespect to the shank part 100 g in the direction around the axis ofrotation 11 of the shank part 100 g is reliably restricted due to thesimple shape.

In addition, in the embodiment, since the conical frustum convex section212 protrudes from the tool part 200 g abutting the workpiece and thelength of the tool part 200 g along the axis of rotation 11 isincreased, strength of the tool part 200 g can be improved.

Hereinafter, an eighth embodiment of the present invention will bedescribed. As shown in FIGS. 18 and 19, a tool for friction stir welding10 h of the embodiment is distinguished from the fifth embodiment inthat, like the fourth embodiment, the conical frustum convex section 112and the key groove 132 are provided at a shank part 100 h and theconical frustum concave section 222 and the key 231 are provided at atool part 200 h. A length of a screw 400 h excluding the screw headsection 401 corresponds to a length obtained by adding a length of thehole section 141 of the shank part 100 h and a length of the screw holesection 241 of the tool part 200 h. The other configurations and actionsof the tool for friction stir welding 10 h are the same as the fourthembodiment and the fifth embodiment.

According to the embodiment, since the protruding key 231 and therecessed key groove 132 are provided, the tool part 200 h can move withrespect to the shank part 100 h in the direction parallel to the axis ofrotation 11 of the shank part 100 h while movement of the tool part 200h with respect to the shank part 100 h in the direction around the axisof rotation 11 of the shank part 100 h is reliably restricted due to thesimple shape.

In addition, in the embodiment, since the conical frustum concavesection 222 is recessed in the tool part 200 h abutting the workpiece,even when the tool part is manufactured using a relatively expensivematerial such as an Ir alloy or the like, manufacturing cost can bereduced by reducing an amount of the material used.

Hereinafter, a ninth embodiment of the present invention will bedescribed. As shown in FIG. 20, a tool for friction stir welding 10 i ofthe embodiment is distinguished from the fifth embodiment in that aserrated shape 151 protruding in a serrated shape and including avertical surface 153 parallel to the axis of rotation 11 of the shankpart 100 i and perpendicular to the direction around the axis ofrotation 11 is provided at a front end of a shank part 100 i. Inaddition, the embodiment is distinguished from the fifth embodiment inthat a length of a screw 400 i excluding the screw head section 401 issufficiently greater than a length obtained by adding a length of thehole section 141 of the shank part 100 i and a length of the screw holesection 241 of a tool part 200 i, and further, a nut 460 is provided atthe screw head section 401 side of the screw 400 i. The nut 460 has agroove formed in the inner periphery and meshed with the groove 404 ofthe outer periphery of the screw 400 i, and has an outer diameter largerthan the inner diameter of the hole section 141. Four serrated shapes151 that include the common vertical surface 153 are disposed at thefront end of the shank part 100 i.

In addition, as shown in FIGS. 20 and 21, the tool for friction stirwelding 10 i of the embodiment is distinguished from the fifthembodiment in that a serrated shape 251 including the vertical surface253 parallel to the axis of rotation 11 of the shank part 100 i andperpendicular to the direction around the axis of rotation 11 isprovided at a bottom section of the base section 205 of the tool part200 i. The serrated shape 251 of the tool part 200 i has a shapecorresponding to a shape of the serrated shape 151 of the shank part 100i, and is disposed to correspond to the disposition of the serratedshape 151 of the shank part 100 i. The four serrated shapes 251 thatinclude the common vertical surface 253 are disposed at the bottomsection of the base section 205 of the tool part 200 i. Further, theshapes and the numbers of the serrated shapes 151 and the serratedshapes 251 may be arbitrarily selected.

Hereinafter, an action of the tool for friction stir welding 10 i of theembodiment will be described. When the friction stir welding isperformed using the tool for friction stir welding 10 i, like the fifthembodiment, the serrated shape 151 of the shank part 100 i and theserrated shape 251 of the tool part 200 i are fitted to each other.

The serrated shape 151 includes the vertical surface 153 parallel to theaxis of rotation 11 of the shank part 100 i and perpendicular to thedirection around the axis of rotation 11, and the serrated shape 251includes the vertical surface 253 parallel to the axis of rotation 11 ofthe shank part 100 i and perpendicular to the direction around the axisof rotation 11. For this reason, the tool part 200 i can move withrespect to the shank part 100 i in the direction parallel to the axis ofrotation 11 of the shank part 100 i while movement of the tool part 200i with respect to the shank part 100 i in the direction around the axisof rotation 11 of the shank part 100 i is reliably restricted.

In the embodiment, as the vertical surfaces 153 and 253 perpendicular tothe direction around the axis of rotation 11 abut each other, when seenfrom the screw head section 401 inserted after that, movement of thetool part 200 i with respect to the shank part 100 i in acounterclockwise direction is reliably restricted. Accordingly, therotational direction of the shank part 100 i upon the friction stirwelding becomes clockwise when seen from the screw head section 401.

As shown in FIG. 20, the screw 400 i passes through the nut 460 whilethe groove 404 of the outer periphery of the screw 400 i and the grooveof the inner periphery of the nut 460 are meshed with each other.

In a state in which the shank part 100 i is disposed between the toolpart 200 i and the nut 460, the groove 404 of the outer periphery of thescrew 400 i that passed through the hole section 141 is meshed with thegroove 244 of the inner periphery of the screw hole section 241. Asshown in FIG. 22, as the nut 460 is rotated in a direction in which thenut 460 and the tool part 200 i approach each other, the tool part 200 iis fixed to the front end of the shank part 100 i.

When the tool part 200 i is detached from the shank part 100 i, first,as shown in FIG. 23, the nut 460 is rotated in the direction in whichthe nut 460 and the tool part 200 i move away from each other.Accordingly, the tool part 200 i and the screw 400 i can move in thedirection parallel to the axis of rotation 11 of the shank part 100 i.

Next, as shown in FIG. 24, the screw 400 i is rotated in the directionin which the vertical surface 153 of the serrated shape 151 of the shankpart 100 i and the vertical surface 253 of the serrated shape 251 of thetool part 200 i that are fitted to each other are separated from eachother. The direction becomes clockwise when seen from the screw headsection 401, and becomes a direction in which the screw 400 i is screwedinto the screw hole section 241. An inclined surface of the serratedshape 251 of the tool part 200 i slides along an inclined surface of theserrated shape 151 of the shank part 100 i, the tool part 200 i ispushed out of the shank part 100 i while rotating, and the tool part 200i is detached from the front end of the shank part 100 i.

Accordingly, the tool part 200 i is reliably fixed to the front end ofthe shank part 100 i by screwing the screw 400 i into the shank part 100i and the tool part 200 i to fasten the nut 460, and then the nut 460 isloosened and the screw 400 i is rotated clockwise when seen from thescrew head section 401, the inclined surface of the serrated shape 251of the tool part 200 i and the inclined surface of the serrated shape151 of the shank part 100 i slide and the tool part 200 i is detachedfrom the shank part 100 i by applying a force in a direction away fromthe shank part 100 i. Accordingly, the tool part 200 i can be easilydetached from the shank part 100 i. Further, a release agent such as BNor the like is applied to the serrated shape 151, the serrated shape251, the screw 400 i, the hole section 141 and the screw hole section241 that come in contact with each other to effectively prevent burning.

Hereinafter, a tenth embodiment of the present invention will bedescribed. As shown in FIG. 25, a tool for friction stir welding 10 j ofthe embodiment is distinguished from the ninth embodiment in that aserrated convex section 161 protruding in a serrated shape and includinga vertical surface 163 parallel to the axis of rotation 11 of the shankpart 100 j and perpendicular to the direction around the axis ofrotation 11 is provided at a columnar concave section 124 recessed in acolumnar shape of a front end of a shank part 100 j. In addition, theembodiment is distinguished from the ninth embodiment in that theincreased hole diameter section 142 having a larger inner diameter thanthe hole section 141 is formed in the hole section 141 of the shank part100 j close to the screw head section 401. For this reason, a length ofa screw 400 j excluding the screw head section 401 corresponds to alength obtained by adding a length of the hole section 141 of the shankpart 100 j smaller than that of the ninth embodiment and a length of thescrew hole section 241 of a tool part 200 j and is smaller than that ofthe screw 400 i of the ninth embodiment, and further, the nut 460 is notprovided. In addition, the groove 404 of the screw 400 j and the groove244 of the screw hole section 241 are formed in a direction in which thescrew 400 j is screwed into the screw hole section 241 when the screw400 j is rotated counterclockwise when seen from the screw head section401.

In addition, as shown in FIGS. 25 and 26, the tool for friction stirwelding 10 j of the embodiment is distinguished from the ninthembodiment in that a serrated concave section 262 recessed in a serratedshape and including a vertical surface 263 parallel to the axis ofrotation 11 of the shank part 100 j and perpendicular to the directionaround the axis of rotation 11 is provided at the bottom section of thebase section 205 of the tool part 200 j. Further, the shapes and thenumbers of the serrated convex section 161 and the serrated concavesection 262 may be arbitrarily selected.

A configuration and an action of the tool for friction stir welding 10 jwill be described. As shown in FIG. 27, as the screw 400 j is screwedinto the shank part 100 j and the tool part 200 j, the tool part 200 jis pulled to the shank part 100 j, and the tool part 200 j can bereliably fixed to the front end of the shank part 100 j.

When the tool part 200 j is detached from the shank part 100 j, first,the screw 400 j is detached from the shank part 100 j. Next, as shown inFIG. 28, a tool part detachment screw 450 j having a sufficientlygreater length than the screw 400 j and the same groove 454 as the screw400 j formed in the outer periphery is screwed into the hole section 141of the shank part 100 j and the screw hole section 241 of the tool part200 j counterclockwise when seen from the screw head section 451.Accordingly, the tool part 200 j and the tool part detachment screw 450j can move in the direction parallel to the axis of rotation 11 of theshank part 100 j.

Further, as shown in FIG. 29, as the tool part detachment screw 450 j isrotated counterclockwise when seen from the screw head section 451, thetool part 200 j is rotated in a direction in which the vertical surfaces163 and 263 that are fitted to each other are separated from each other.The inclined surface of the serrated concave section 262 of the toolpart 200 j and the inclined surface of the serrated convex section 161of the shank part 100 j slide and the tool part 200 j is detached fromthe shank part 100 j by applying a force in a direction away from theshank part 100 j. Accordingly, the tool part 200 j can be easilydetached from the shank part 100 j.

Further, in the ninth embodiment, while the shank part 100 i isconfigured to be rotated clockwise when seen from the screw head section401, in the embodiment, the shank part 100 j is configured to be rotatedcounterclockwise when seen from the screw head section 401. Directionsin which the shank parts 100 i and 100 j are rotated differ according tothe friction stir welding apparatus. However, as described in the ninthembodiment and this embodiment, design changes of the shank parts 100 iand 100 j and the tool parts 200 i and 200 j may be performed accordingto the rotational direction of the friction stir welding apparatus.

Further, a plurality of configurations of the increased hole diametersection 142, the hexagonal frustum-shaped concave section 121 and thehexagonal frustum-shaped convex section 211, the hexagonalfrustum-shaped convex section 111 and the hexagonal frustum-shapedconcave section 221, the conical frustum concave section 122 and theconical frustum convex section 212, the key 131 and the key groove 232,the conical frustum convex section 112 and the conical frustum concavesection 222, the key groove 132 and the key 231, the serrated shape 151and the serrated shape 251, and the serrated convex section 161 and theserrated concave section 262 of the fifth to tenth embodiments may beappropriately selected and combined with each other. In addition, evenin the ninth and tenth embodiment, like the fifth embodiment, the toolparts 200 i and 200 j can be attached to the shank parts 100 i and 100 jusing the screw 400 e, and further, the tool parts 200 i and 200 j canbe detached from the shank parts 100 i and 100 j using the tool partdetachment screw 450 e.

Hereinafter, an eleventh embodiment of the present invention will bedescribed. As shown in FIG. 30, the tool for friction stir welding 10 kaccording to the eleventh embodiment of the present invention includes ashank part 100 k, a tool part 200 k and a lid section 500.

As shown in FIGS. 30 to 32, a dovetail groove section 172 recessed in atrapezoidal shape and extending in the direction perpendicular to theaxis of rotation 11 is formed at a front end that is an upper end of ashank part 100 k of FIG. 30. One end of the direction perpendicular tothe axis of rotation 11 of the dovetail groove section 172 is opened inan outer periphery direction of the shank part 100 k by a lid-attachingcutout 181 having a shape corresponding to a shape of a lid section 500.The other end in the direction perpendicular to the axis of rotation 11of the dovetail groove section 172 terminates at the inside of the shankpart 100 k without reaching the outer periphery of the shank part 100 k.The lid-attaching cutout 181 has a pair of lid-attaching screw holesections 145. The shank part 100 k has a tool part detachment screw holesection 146 formed from an end portion of the dovetail groove section172 that terminates at the inside of the shank part 100 k to the outerperiphery of the shank part 100 k. Both of the lid-attaching screw holesection 145 and the tool part detachment screw hole section 146 havegrooves formed at inner periphery thereof.

As shown in FIGS. 30 to 32, a dovetail-shaped section 271 having a shapecorresponding to a shape of the dovetail groove section 172 of the shankpart 100 k and protruding in a trapezoidal shape is formed at the bottomsection of the tool part 200 k. Further, in the embodiment, adovetail-shaped section may be formed at the shank part 100 k, and adovetail groove section may be formed in the tool part 200 k.

As shown in FIGS. 30 and 31, the lid section 500 has a shapecorresponding to a shape of the lid-attaching cutout 181 of the shankpart 100 k. The lid section 500 has a screw hole section 501 formed at aposition corresponding to the lid-attaching screw hole section 145 ofthe shank part 100 k.

Hereinafter, an action of a tool for friction stir welding 10 k of theembodiment will be described. When the friction stir welding isperformed using the tool for friction stir welding 10 k, as shown inFIGS. 31 and 32, the dovetail groove section 172 of the shank part 100 kand the dovetail-shaped section 271 of the tool part 200 k are fitted toeach other. The dovetail groove section 172 extends in the directionperpendicular to the axis of rotation 11. For this reason, the tool part200 k can slide with respect to the shank part 100 k in the directionperpendicular to the axis of rotation 11 of the shank part 100 k whilemovement of the tool part 200 k with respect to the shank part 100 k inthe direction parallel to the axis of rotation 11 of the shank part 100k is restricted. The dovetail-shaped section 271 is inserted into thedovetail groove section 172 until the dovetail-shaped section 271 abutsthe end portion of the dovetail groove section 172 that terminates atthe inside of the shank part 100 k.

In a state in which the dovetail groove section 172 and thedovetail-shaped section 271 are fitted to each other, the lid section500 is attached to the lid-attaching cutout 181 by a lid sectionattachment screw 601. As the lid section attachment screw 601 isattached, the tool part 200 k cannot slide with respect to the shankpart 100 k in the direction perpendicular to the axis of rotation 11 ofthe shank part 100 k, and the tool part 200 k is fixed to the front endof the shank part 100 k. Further, a release agent such as BN or the likeis applied to the dovetail groove section 172, the dovetail-shapedsection 271 and the lid section 500 that come in contact with each otherto effectively prevent burning.

When the tool part 200 k is detached from the shank part 100 k, sincethe lid section 500 is detached from the shank part 100 k, a tool partdetachment screw 602 is screwed into the tool part detachment screw holesection 146, and a force is applied to the dovetail-shaped section 271of the tool part 200 k at the front end of the tool part detachmentscrew 602, even when the tool part 200 k is hard to remove, the toolpart 200 k can be easily detached from the shank part 100 k.

In the embodiment, the tool for friction stir welding includes the toolpart 200 k abutting the workpiece while rotating, the shank part 100 kconfigured to fix the tool part 200 k to the front end and rotatedtogether with the tool part 200 k, and the lid section 500 fixed to thelid-attaching cutout 181 in which the tool part 200 k and the shank part100 k come in contact with each other. The dovetail-shaped section 271protruding in the trapezoidal shape and the dovetail groove section 172recessed in the trapezoidal shape are formed at portions of the toolpart 200 k and the shank part 100 k in which the tool part 200 k and theshank part 100 k come in contact with each other such that the tool part200 k can slide with respect to the shank part 100 k in the directionperpendicular to the axis of rotation 11 of the shank part 100 k whilemovement of the tool part 200 k with respect to the shank part 100 k inthe direction parallel to the axis of rotation 11 of the shank part 100k is restricted because the tool part and the shank part are fitted toeach other. After the dovetail-shaped section 271 and the dovetailgroove section 172 of the tool part 200 k and the shank part 100 k arefitted to each other, as the lid section 500 is fixed to thelid-attaching cutout 181 in which the tool part 200 k and the shank part100 k come in contact with each other to restrict slide movement of thetool part 200 k with respect to the shank part 100 k in the directionperpendicular to the axis of rotation 11 of the shank part 100 k, thetool part 200 k is fixed to the front end of the shank part 100 k.

For this reason, when the lid section 500 is fixed to the lid-attachingcutout 181, since movement of the tool part 200 k with respect to theshank part 100 k in the direction parallel to the axis of rotation 11 ofthe shank part 100 k is restricted by the dovetail-shaped section 271and the dovetail groove section 172 that are fitted to each other andslide movement of the tool part 200 k with respect to the shank part 100k in the direction perpendicular to the axis of rotation 11 of the shankpart 100 k is restricted by the lid section 500, upon rotation of theshank part 100 k, fixation of the tool part 200 k and the shank part 100k can be reliably prevented from being loosened, and the tool part 200 kcan be reliably prevented from falling out of the shank part 100 k.Meanwhile, when the lid section 500 is detached, even though thedovetail-shaped section 271 and the dovetail groove section 172 arefitted to each other, since the tool part 200 k can move with respect tothe shank part 100 k in the direction perpendicular to the axis ofrotation 11 of the shank part 100 k, the tool part 200 k can be easilydetached from the shank part 100 k.

In addition, according to the embodiment, the tool part detachment screwhole section 146 configured to attach the tool part detachment screw 602by applying a force such that the tool part 200 k slides with respect tothe shank part 100 k in the direction perpendicular to the axis ofrotation 11 of the shank part 100 k when the dovetail-shaped section 271and the dovetail groove section 172 of the tool part 200 k and the shankpart 100 k are fitted to each other and the lid section 500 is not fixedto the lid-attaching cutout 181 in which the tool part 200 k and theshank part 100 k come in contact with each other. Accordingly, as thetool part detachment screw 602 is attached to the tool part detachmentscrew hole section 146 and a force is applied by the tool partdetachment screw 602 such that the tool part 200 k slides with respectto the shank part 100 k in the direction perpendicular to the axis ofrotation 11 of the shank part 100 k, even when the tool part 200 k ishard to remove, the shank part 100 k can be more easily detached.

Further, the present invention is not limited to the embodiments but adetachment/attachment method may be modified in various forms, forexample, by forming the tool part detachment screw hole section 146 as athrough-hole with no groove, forming a screw hole section in the toolpart and screwing the screw thereinto to fix the dovetail-shaped section271, and so on.

INDUSTRIAL APPLICABILITY

According to the tool for friction stir welding of the one aspect andthe other aspects of the present invention, fixation between the toolpart and the shank part can be prevented from being loosened, the toolpart can be reliably prevented from falling out of the shank part, andthe tool part can be easily detached from the shank part.

REFERENCE SIGNS LIST

10 a to 10 k . . . tool for friction stir welding; 11 . . . axis ofrotation; 100 a to 100 k . . . shank part; 111 . . . hexagonalfrustum-shaped convex section; 112 . . . conical frustum convex section;121 . . . hexagonal frustum-shaped concave section; 122 . . . conicalfrustum concave section; 124 . . . columnar concave section; 131 . . .key; 132 . . . key groove; 141 . . . hole section; 142 . . . increasedhole diameter section; 144 . . . groove; 145 . . . lid-attaching screwhole section; 146 . . . tool part detachment screw hole section; 151 . .. serrated shape; 153 . . . vertical surface; 161 . . . serrated convexsection; 163 . . . vertical surface; 172 . . . dovetail groove section;181 . . . lid-attaching cutout; 200 a to 200 k . . . tool part; 201 . .. shoulder; 202 . . . probe; 205 . . . base section; 211 . . . hexagonalfrustum-shaped convex section; 212 . . . conical frustum convex section;213 . . . collar; 221 . . . hexagonal frustum-shaped concave section;222 . . . conical frustum concave section; 231 . . . key; 232 . . . keygroove; 241 . . . screw hole section; 244 . . . groove; 251 . . .serrated shape; 253 . . . vertical surface; 262 . . . serrated concavesection; 263 . . . vertical surface; 271 . . . dovetail-shaped section;300 . . . cap part; 301 . . . cap part inner surface; 302 . . . reduceddiameter section; 400 e to 400 j . . . screw; 401 . . . screw headsection; 402 . . . screw front end portion; 404 . . . groove; 450 e, 450j . . . tool part detachment screw; 451 . . . screw head section; 452 .. . screw front end portion; 454 . . . groove; 460 . . . nut; 500 . . .lid section; 501 . . . screw hole section; 601 . . . lid sectionattachment screw; 602 . . . tool part detachment screw.

1. A tool for friction stir welding comprising: a tool part abutting aworkpiece while being rotated; a shank part configured to fix the toolpart to a front end of the shank part and be rotated together with thetool part; and a cap part configured to cover the tool part and theshank part, wherein portions in the tool part and the shank part atwhich the tool part and the shank part contact each other have at leastone from between a convex section and a concave section, in order toenable movement of the tool part with respect to the shank part in adirection parallel to an axis of rotation of the shank part whilemovement of the tool part with respect to the shank part in a directionaround the axis of rotation of the shank part is restricted, by theconvex section and the concave section of the tool part and the shankpart being fitted to each other, and after the convex section and theconcave section of the tool part and the shank part are fitted to eachother, the tool part is fixed to the front end of the shank part, by thetool part and the shank part being covered by the cap part.
 2. The toolfor friction stir welding according to claim 1, wherein the convexsection is a shape protruding in either a polygonal conical shape or apolygonal frustum shape, and the concave section is a shape recessed ineither a polygonal conical shape or a polygonal frustum shape.
 3. Thetool for friction stir welding according to claim 1, wherein the convexsection is a protruding shape as a key, and the concave section has arecessed shape as a key groove.
 4. The tool for friction stir weldingaccording to claim 1, wherein the convex section has a serrated shapeincluding a surface parallel to the axis of rotation of the shank partand perpendicular to the direction around the axis of rotation, and theconcave section has a serrated shape including a surface parallel to theaxis of rotation of the shank part and perpendicular to a directionaround the axis of rotation.